All of a sudden my 99 v70's a/c compressor stops and then comes on again. What should I be looking for? It is ice cold went it works.

 

sounds like either your freon level is low or the AC clutch gap is too wide and needs to be reshimmed. First is use a pressure gauge on the low port to measure pressure with the AC running. If low, add some freon. If the freon level is good, it may be the AC clutch. What happens is as the clutch heats up, it loses its magnetic grip and fails until it cools off again. Check youtube vids and other posts on how to fill the freon and how to reshim.

 

Thanks for the reply mt6127, the compressor sounds interesting. It seems when I am driving at highway speeds no matter how long, it never shuts off. Only when I am in stop and go and not all the time. The a/c is ice cold while it is working. Do you think it still is the ac clutch?

 

typically the clutch gap problem shows up on the hottest days... On my 850, it would work fine on moderately warm days, then shut off on a hot day highway or not - only to come back after it cooled some. It would work fine for say 15 minutes then cut out on the hot days. So I think its still possibly the clutch but I'd start with the freon pressure first since that's an easy fix. There's also the "bread clip" fix for the clutch - but that only works on certain style clutches. Youtube vids are available to see how. The only other thing I can think of is a wonky temp sensor, but those would likely throw a code (ie does the AC and Recirc lights ever flash?) You'd need a scanner or DICE capable of reading the "chassis" codes not just the powertrain codes to see.